The present invention relates to fuel systems for motor vehicles, and, more specifically, to a capless refueling assembly at the end of a filler tube, which assembly opens and closes automatically upon insertion and removal of a fuel dispensing nozzle, and has break-away features in the event of a collision, promoting continued vehicle fuel system integrity.
Vehicle fuel systems commonly include a fuel tank and a filler tube through which fuel is dispensed into the tank. A removable cap is provided at the end of the filler tube, to close the tube. Heat, movement of the vehicle and the like can cause a build-up of vapor pressure in the fuel tank. Under some conditions, vapor and/or fuel droplets can be discharged from the neck of the filler tube, as the cap is removed from the end of the filler tube. In addition to the unpleasant side affects from being sprayed with fuel and/or vapor, a person can be placed in danger from fire or explosion of the highly volatile substances.
It is known to provide a positive sealing insert, or PSI, in the end of the filler tube, to vent vapors that accumulate in the tank. The PSI includes a valve that functions to limit back flow of fuel into the outermost area of the filler tube, if the fuel sloshes up the filler tube during operation of the vehicle. A removable fuel cap commonly covers the end of the filler tube, and the cap provides a barrier against dirt or other contaminants from reaching the PSI and fouling the operation thereof, as well as providing a primary fuel shutoff.
Several problems have been experienced with known designs of refueling assemblies. Fuel caps can be lost, and the replacement thereof is often forgotten after refueling is complete. It is known to attach the fuel cap to the vehicle using a flexible tether strap secured to the housing surrounding the filler tube, to prevent loss of the cap. Tether straps used in the past have been relatively short, and some individuals find the strap to be awkward and interfering as the fuel cap is replaced. Further, the nature of such straps has been such as to require the strap and cap to be held out of the way with one hand while the refueling nozzle is inserted into the filler tube with the other hand. These factors can make a refueling operation awkward and slow for many people, but especially for some elderly individuals and others having physical limitations.
While a tether strap may prevent loss of the cap, it does not ensure that the cap will be replaced each time refueling is completed. Without replacement of the cap, or with improper replacement of the cap, the closure system is not complete. Dirt and contaminants can enter the filler tube, potentially fouling the PSI, and interfering with proper operation and function thereof. It is also possible for the tether strap to fail, resulting in an unconnected cap, and again raising the potential for the cap to be lost or forgotten during a refueling procedure.
Capless systems have been proposed in the past. Many such systems are complex and costly. Some are confusing and difficult to use, requiring training or instruction in the proper use thereof. Others may not protect adequately the intricate parts of the refueling system from dust or grime that will interfere with proper operation.
Another problem associated with refueling assemblies of vehicle fuel systems involves the accumulation of liquids in the housing surrounding the end of the filler tube. Many embody a cavity or chamber in which the end of the tube and the fuel cap are disposed. Water from rain, melting snow and vehicle washing can accumulate in the chamber. Small amounts of fuel can drip from a fuel-dispensing nozzle during a refueling operation, as the nozzle is removed from the filler tube. The fuel can attract dust and grime, which accumulate over time. During hand washing, it is common for water to be sprayed from a hose or pressure washer into the chamber, in an effort to clean the chamber. Any end closure for the filler tube, including a capless end closure, should withstand direct high-pressure spray from various angles, without compromising the sealing effect of the closure. The accumulation of water in the chamber, from any source, can enter the filler tube, particularly if the cap is removed therefrom for refueling, or at any time if the cap has been lost or not properly and tightly closed on the end of the filler tube.
Vehicle crash-worthiness requires that fuel system structural integrity remain in the event of a crash, including integrity of the tank, filler tube and a closure therefore, so that fuel does not leak and create a fire danger. This can present design challenges in attaching end closure assemblies since the fuel tank is often connected to the frame and the filler tube extends through or near to outer fender bodies that may be highly damaged during a crash.
The present invention is directed to overcoming one or more of the problems identified above by providing a breakaway capless refueling assembly that is simple and intuitive to use, operates in conjunction with common positive sealing inserts, and limits the accumulation of fluids in the housing chamber surrounding the end of the filler tube, while functioning to retain filler tube integrity during a crash.
The present invention provides a closure mechanism for the end of a fuel system filler tube, which opens and closes as a refueling nozzle is inserted or removed, and which channels away any accumulated liquids in the chamber, withstands direct high-pressure spray, and separates from the PSI in the event of a crash, promoting fuel system integrity.
In one aspect thereof, the invention provides a capless refueling assembly for an automobile fuel system with a filler tube assembly including a filler tube and a positive sealing insert associated with the filler tube. A cover structure is provided for protecting the positive sealing insert. The cover structure includes a housing defining a chamber having a bottom. The bottom defines a hole in substantial alignment with the filler tube. A closure mechanism disposed in the chamber includes an arm pivotally mounted in the chamber and an enlargement on the arm for selectively covering and exposing the hole. A frangible connection secures the cover structure to the filler tube assembly for facilitating separation of the cover structure from the filler tube assembly under pre-established conditions.
In another aspect thereof, the invention provides a capless refueling assembly for receiving fuel from a refueling system. The assembly includes a filler tube for receiving an input of fuel. The filler tube has an end adapted to receive a dispensing nozzle therein. A housing defines a chamber surrounding the filler tube end. The chamber has a hole in substantial alignment with the filler tube. An arm is attached to the chamber about a pivot. An enlargement at an end of the arm selectively covers and uncovers the hole. A first sealing surface in the chamber around the hole and a second sealing surface on the enlargement cooperate to sealingly close the chamber hole.
In yet another aspect thereof, the invention provides a cover structure for an end of a vehicle fuel filler tube adapted to receive a dispensing nozzle of a refueling system. The cover structure includes a first housing part and a second housing part joined together and defining a chamber at the filler tube end. The chamber has a hole in substantial alignment with the filler tube, an arm attached to the chamber about a pivot, and an enlargement at an end of the arm for selectively covering and uncovering the hole. A first sealing surface in the chamber around the hole and a second sealing surface on the enlargement cooperate to sealingly close the chamber hole. The first and second sealing surfaces are urged into sealing engagement.
An advantage of the present invention is providing a closure mechanism for the end of a fuel system filler tube for which the proper use is intuitive, which opens readily in response to the start of a refueling procedure, and which closes automatically upon completion of refueling.
Another advantage of the present invention is providing a refueling assembly with structure for draining liquids away from the filler tube end and out of a chamber surrounding the filler tube end, and which is simple in operation and inexpensive to manufacture and install.
Still another advantage of the present invention is providing a filler tube closure mechanism that connects to a positive sealing insert with breakaway connections so that a fuel tank and filler tube with sealing insert therein can withstand crashes without spilling fuel.
Yet another advantage of the present invention is providing a capless refueling assembly that guides a refueling nozzle through the PSI without damage to the sealing portions of the PSI, and provides a locking lip to hold a refueling nozzle during a refueling process.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features.